Sewage is either cpllected ...

Sewage is either cpllected and stored in septic tanks and removed periodically with honey sucker trucks or by sewage piping system. Either way treatment can be achieved using Swami Valmiki Sreenivasa Ayyangarya's Vedic Sciences methods already outlined in other discussions in this The Water Network.

In this particular query for a mobile treatment system, there must be a storage tank which keeps the sewage collected and ready for treatment and/or removal. With Swami Valmiki's methods, treatment can be started and completed upto a desired stage, within the storage tank / septic tank, as the case may be. However, another second tank can help avert the removal of untreated human excreta which can arrive, since sewage generation is continuous. It can also be a series of tanks depending upon space availability and volume of sewage generated on a 24 hr basis, keeping shock loads as parameters for calculation of quantities to be treated.

In this second alternative, the first treatment tank will gradully get fillied up with Inactive sludge, since treated grey water is being removed and taken to the second tank and so on, if there are several tanks.

The resultant products are: Treated grey water and Inactive sludge. The grey water can be sucked out and remaining sludge can be dewaterd or carted away in a wet condition,

Both the grey water and Inactive sludge will be odour free , particularly mal odour commonly associated with sewage treatment plants, after this first level of treatment. since pathogens do not breed either in the Inactive sludge or treated grey water ,Inactive sludge will be safe to handle with manual removal methods to keep costs down or a mechanical bucker excavator to shovel the treated bio solids as Inactive sludge onto a removal truck.

In case a the whole system at each site needs to have a small foot print , A belt filter can help in complete dewatering .If such compact and small size belt filters are available (I think they are available), it can be transported from site to site in a truck.
The grey water can be used straight away for watering gardens and parks or for irrigation in peri urban areas.The inactive sludge is very useful as soil conditioner in farmlands which lack organic content which helps retain moisture and reduces load on need for irrigation.